Analog Integrated Circuit Design 2nd Edition

Chapter 16 Solutions

Compiled by:

Tony Chan Carusone

Solutions contributed by:

Tony Chan Carusone

Ali Sheikholeslami & Khoman Phang (1st ed. Solutions)

Q 16.1)

Q 16.2)

Q 16.3)

Q 16.4)

Q 16.5)

Q 16.6)

The matching accuracy required for the b2 resistor, b3 resistor, and b4 resistor is 2 times, 4

times, and 8 times the matching accuracy of the b1 resistor, respectively.

Q 16.7)

Q 16.8)

Q 16.9)

Q 16.10)

Q 16.11)

Q 16.12)

Q 16.13)

Q 16.14)

Q 16.15)

Q 16.16)

Q 16.17)

Q 16.18)

Q 16.19)

The currents in each branch of the circuit are illustrated below.

The minimum output voltage occurs at Vout when all currents are steered towards the opamp

feedback resistor, R/2. In this state, the total current through the feedback resistor is

63

2 2 2 4 8 16 32 32

ref ref ref ref ref ref ref ref

tot

V V V V V V V VI

R R R R R R R R

When this current passes through R/2, the output voltage becomes

63 63

·2 32 2 64

ref

out tot ref

VR RV I V

R

With all switches in the opposite position, the current through R/2 is zero and the output

voltage reaches its maximum value equal to the ground potential, 0V. Hence the achievable

peak-to-peak output swing is 63

64refV

Q 16.20)

The switches’ (W/L) ratios must be sized in proportion to the current they carry. Illustrated

below are all of the branch currents, along with the relative switch sizes required to handle

those branch currents.